scholarly journals Hydrothermal Synthesis of Euhedral Co3O4 Nanocrystals via Nutrient-Assisted Topotactic Transformation of the Layered Co(OH)2 Precursor under Anoxic Conditions: Insights into Intricate Routes Leading to Spinel Phase Development and Shape Perfection

2020 ◽  
Vol 20 (12) ◽  
pp. 7771-7787
Author(s):  
Joanna Gryboś ◽  
Camillo Hudy ◽  
Angelika Gryczynska ◽  
Witold Piskorz ◽  
Zbigniew Sojka
Keyword(s):  
Hydrothermal Synthesis ◽  
Spinel Phase ◽  
Anoxic Conditions ◽  
Phase Development ◽  
Topotactic Transformation

Microstructural observations of the “Wustite-Spinel” coexistence following quenching of cation-excess spinels, Ni2(1+x)Ti1-xO4

1990 ◽  
Vol 48 (4) ◽  
pp. 1058-1059
Author(s):  
Ian M. Anderson ◽  
Arnulf Muan ◽  
C. Barry Carter
Keyword(s):  
Film Growth ◽  
Spinel Phase ◽  
Model Systems ◽  
Ion Milling ◽  
Coexistence Of Phases ◽  
Nonequilibrium Conditions ◽  
Diffraction Patterns ◽  
Spinel Structures ◽  
Highly Porous ◽  
Standard Techniques

Oxide mixtures which feature a coexistence of phases with the wüstite and spinel structures are considered model systems for the study of solid-state reaction kinetics, phase boundaries, and thin-film growth, and such systems are especially suited to TEM studies. (In this paper, the terms “wüstite” and “spinel” will refer to phases of those structure types.) The study of wüstite-spinel coexistence has been limited mostly to systems near their equilibrium condition, where the assumptions of local thermodynamic equilibrium are valid. The cation-excess spinels of the type Ni2(1+x)Ti1-xO4, which reportedly exist only above 1375°C4, provide an excellent system for the study of wüstite-spinel coexistence under highly nonequilibrium conditions. The nature of these compounds has been debated in the literature. X-ray and neutron powder diffraction patterns have been used to advocate the existence of a single-phase, non- stoichiometric spinel. TEM studies of the microstructure have been used to suggest equilibrium coexistence of a stoichiometric spinel, Ni2TiO4, and a wüstite phase; this latter study has shown a coexistence of wüstite and spinel phases in specimens thought to have been composed of a single, non- stoichiometric spinel phase. The microstructure and nature of this phase coexistence is the focus of this study. Specimens were prepared by ball-milling a mixture of NiO and TiO2 powders with 10 wt.% TiO2. The mixture was fired in air at 1483°C for 5 days, and then quenched to room temperature. The aggregate thus produced was highly porous, and needed to be infiltrated prior to TEM sample preparation, which was performed using the standard techniques of lapping, dimpling, and ion milling.

Hydrothermal synthesis of MoS 2 nanoflowers and their capacitive property

2019 ◽  
Vol 14 (5) ◽  
pp. 493-495 ◽  
Author(s):  
Qinghua Yang ◽  
Chunni Xiao ◽  
Bingbing Chen ◽  
Lin Ma ◽  
Limei Xu
Keyword(s):  
Hydrothermal Synthesis ◽  
Capacitive Property

Hydrothermal Synthesis and Solid-State Laser Refrigeration of Ytterbium-Doped Potassium Lutetium Fluoride (KLF) Microcrystals

2020 ◽  
Author(s):  
Xiaojing Xia ◽  
Anupum Pant ◽  
Xuezhe Zhou ◽  
Elena Dobretsova ◽  
Alex Bard ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Solid State ◽  
Information Science ◽  
Point Group ◽  
Solid State Laser ◽  
Lanthanide Ions ◽  
Group Symmetry ◽  
Luminescence Spectra ◽  
Crystalline Phases ◽  
State Laser

Fluoride crystals, due to their low phonon energies, are attractive hosts of trivalent lanthanide ions for applications in upconverting phosphors, quantum information science, and solid-state laser refrigeration. In this article, we report the rapid, low-cost hydrothermal synthesis of potassium lutetium fluoride (KLF) microcrystals for applications in solid-state laser refrigeration. Four crystalline phases were synthesized, namely orthorhombic K<sub>2</sub>LuF<sub>5</sub> (Pnma), trigonal KLuF<sub>4</sub> (P3<sub>1</sub>21), orthorhombic KLu<sub>2</sub>F<sub>7</sub> (Pna2<sub>1</sub>), and cubic KLu<sub>3</sub>F<sub>10</sub> (Fm3m), with each phase exhibiting unique microcrystalline morphologies. Luminescence spectra and emission lifetimes of the four crystalline phases were characterized based on the point-group symmetry of trivalent cations. Laser refrigeration was measured by observing both the optomechanical eigenfrequencies of microcrystals on cantilevers in vacuum, and also the Brownian dynamics of optically trapped microcrystals in water. Among all four crystalline phases, the most significant cooling was observed for 10%Yb:KLuF<sub>4</sub> with cooling of 8.6 $\pm$ 2.1 K below room temperature. Reduced heating was observed with 10%Yb:K<sub>2</sub>LuF<sub>5</sub>

Hydrothermal Synthesis and Photocatalytic Properties of Cu-doped BiVO4 Microsheets

2013 ◽  
Vol 28 (3) ◽  
pp. 287-294 ◽  
Author(s):  
Guo-Cong LIU ◽  
Zhen JING ◽  
Xi-Bing ZHANG ◽  
Xian-Feng LI ◽  
Hong LIU
Keyword(s):  
Hydrothermal Synthesis ◽  
Photocatalytic Properties

Study on Sol-hydrothermal Synthesis of TiO2 Nanoparticles and their Photoelectric Properties Sensitized by Dye

2009 ◽  
Vol 24 (6) ◽  
pp. 1110-1114 ◽  
Author(s):  
Ji-Yuan ZHANG ◽  
Han-Min TIAN ◽  
Zhi-Peng TIAN ◽  
Xiang-Yan WANG ◽  
Tao YU ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Photoelectric Properties
Sign in / Sign up

Export Citation Format

Share Document